Mount backup scripts from /config/backup on host.

Portainer CE git stacks cannot bind-mount relative repo paths; sync auxiliary files to the host path documented in README.

stacks/backup/docker-compose.yml

@@ -36,8 +36,8 @@ services:
       - /storage1/labdata/romhacks/metadata:/backup/labdata/romhacks/metadata:ro
       - /storage1/labdata/romhacks/library:/backup/labdata/romhacks/library:ro
       - /storage1/labdata/romm/assets:/backup/labdata/romm/assets:ro
-      - ./init-kopia.sh:/init-kopia.sh:ro
-      - ./snapshot-paths.txt:/snapshot-paths.txt:ro
+      - /config/backup/init-kopia.sh:/init-kopia.sh:ro
+      - /config/backup/snapshot-paths.txt:/snapshot-paths.txt:ro
     ports:
       - "51515:51515"
     entrypoint: ["/bin/sh", "/init-kopia.sh"]
@@ -54,10 +54,10 @@ services:
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock:ro
       - /config/backup/dumps:/dumps
-      - ./scripts/backup-dump-databases.sh:/scripts/backup-dump-databases.sh:ro
-      - ./scripts/backup-run-snapshots.sh:/scripts/backup-run-snapshots.sh:ro
-      - ./snapshot-paths.txt:/snapshot-paths.txt:ro
-      - ./crontab:/etc/crontab:ro
+      - /config/backup/scripts/backup-dump-databases.sh:/scripts/backup-dump-databases.sh:ro
+      - /config/backup/scripts/backup-run-snapshots.sh:/scripts/backup-run-snapshots.sh:ro
+      - /config/backup/snapshot-paths.txt:/snapshot-paths.txt:ro
+      - /config/backup/crontab:/etc/crontab:ro
     entrypoint: ["/bin/sh", "-c"]
     command:
       - |